Pneumatic polishing and abrading machine



3 Sheets- Sheet l Sept. 10, 1940. E. AHLSKOG.

PNEUMATIC POLISHING AND ABRADING MACHINE Fixed nec. s. lesa \u/H| 1||||||II..IIIIOIIIIIIIIIII+W BY WM/wf Sept. 10, 1940. E. AHLsKoG2,214,189

PNEUMATIC POLISHING AND ABRADING MACHINE Filed Dec. 5, 193e vssheets-sheet 2 INVENTOR f ERA/57' .4H/.5K06

BY www' ATTORNEY.

Sept. 10, l940 E. AHLsKoG PNEUMATIC POLISHING AND ABRADING MACHINE 3Sheets-Sheet 3 mmv INV ENTOR. EPN-5 734/!5/106 www ATTORNEY.

Patented Sept. 10, 1940 PATENT OFFICE PNEUMATTC POLISHING AND ABRADINGMACHINE Ernst Ahlskog, Chicago, Ill.

Application December 3,

8 Claims.

This invention has to do with a pneumatic tool Y or the like, andrelates particularly to a portable pneumatically operated polishing orabrading machine. l.

The primary object of the present invention is the provision of animproved machine provided with a reciprocating work member powered by afluid working medium controlled by a rotary valve of such machine.

A further object of the present invention is the. provision of animproved polishing machine operated by a uid working medium and adaptedto exhaust such medium upon a surface undergoing treatment thereby forcleaning the same.

15 A further object of the present invention is the provision of animproved clamp member for detachably securing a surface-treating sheetupon the-work member of the machine.

Other desirable objects of my invention will 29 become apparent whenreading the following description in conjunction with the'annexed threesheets of drawings constituting apart of this application, and wherein:

Fig. 1 is a vertical sectional view taken through 25 a preferredembodiment of the invention, as indicated on the line I-I of Fig. 2;

Fig. 2 is a transverse sectional view taken on the line 2--2 of Fig. 1;

Figs. 3, i and 5 are horizontal views taken 3o respectively on the lines3 3, 4--4 and 5-5 of Fig. 1;

- Fig. 6 is an end elevational View taken on the line S- of Fig'. 1;

Fig. 'l is a fragmentary side elevation of the 35 machine;

Fig. 8 is a side elevation of a clamp device employed upon the presentmachine;

Fig. 9 is a view similar to Fig. 8, but illustrate ing a backing pad foran abrasive or polishing 40 sheet; and

Fig. 10 is a transverse sectional View tak'en on the line IIl-I of Fig.9.

The same reference characters where used in several figures vof thedrawings and hereinafter 45 in the description designate the samerespective parts of the machine.

Although the machine herein .described is referred to as a polishingmachine, it will be conceived that said machine may be used for abradoing as well as polishing, or that the work member thereof may be usedfor performing other services when operably connected with suitableadaptor parts.

Referring now to the drawing and particularly 55 to Figs. 1 to 4, themachine will be seen to com- 1938, Serial No. 243,751

prise a casing I0 which is provided on its upper side with hollowstandards II for the attachment of a handle member I2. A pair of similar'cylinders I3 are axially aligned within the casing Ill to which theyare secured at their outer and opposite endsby means of machine screwsI4. The cylinders I3 are provided with slots I5 in diametricallyopposite sides thereof.

Between the opposed inner ends of the cylinders I3 there is disposed avalve A including a casing I6 which is drilled for receiving bolts I'I,Figs. 2 and 3. Bolts I'I also extend through flanges I8 upon the innerends of the cylinders I3, and when the nuts I9 are threaded onto saidbolts the cylinders i3 and the valve chamber I6 are drawn tightly into aunitary assembly. Gasket members 20 may be placed between the ends ofthe anges I8 and the valve casing I6 for providing a gas-tight sealbetween these parts.

The valve casing I6 is provided with a horizontal intake passage 2l andan exhaust passage 22. These passages 2| and 22 communicate with acylindrical valve chamber 23 Within which there is disposed a rotatablevalve member 24. Said valve member is freely rotatable upon a verticalshaft 25. Diametrically opposite corners 25 of the valve member 24 arechamfered to facilitate the admission of gas or other fluid Workingmedium to one of the cylinders I3, and the exhaust of such medium fromthe other of said cylinder while the valve member is in a centeredposition as that illustrated in Fig. 4. Lateral passages 21 in oppositesides of the valve casing I6 communicate with the cylinders I3. Saidpassages 21 permit the admittance and discharge of working medium to andfrom the cylinders under control of the valve A. Each of the cylindersI3 contains a piston 28. Said pistons are axially drilled at 29 andthreaded for cooperating with the threaded portions of bolts 30 of whichthe heads serve to hold cupwashers .3l upon the inner ends of thepistons. Said washers 3| may be made of leather and serve the samepurpose as conventional piston rings for precluding the escapeof uidpast the pistons. Paired apertured ears 32 project outwardlyv from theouter ends of the pistons 28, there being a pin 33 disposed between andanchored in the apertures of the paired ears upon each of the pistons.The pins 33 are for supporting a reciprocal carriage B comprising a workmember 34 and ayoke 35.

The carriage B also comprises vertical cross members 36 of which centralsections, containing oblong apertures 31, are disposed between theapertured ears 32 on the pistons 28. -Said apertures 31 receive the pins33 and therebyr connect the carriage B with both of the pistons 28.

The lower end sections 38 of the cross members 36 are threaded andextend through apertured bosses 39 projecting upwardly from oppositeends of the work member 34. Said bosses 39 are countersunk at 48 intheir lower sides for receiving nuts 4I which are threaded onto thelower end sections 38 of said cross members. The right-hand boss 39,Fig. 1, has in its upper end a cut-away section 42 which accommodatesone end of an olf-set connecting rod 43. Said end of the connecting rodis provided with a bushing 44 which is journalled on the lower section38 of the right-hand cross member 36. This connecting rod is forrotating the valve member 24 during operation of the device in themanner and for the purpose hereinafter fully described.

The upper ends of the cross members project through openings in oppositeends of the yoke 35. Said yoke comprises side pieces 46 which extendalong opposite sides of the Valve casing I6 as clearly illustrated in'Figs. 2 and 3. The upper and lower sides of the carriage B which arerespectively formed by the yoke and the work member or shoe 34 is arigid assembly which is connected with both of the pistons 28, and ismovable in. unison therewith. During such movement the slots I5 in theupper and lower side walls of cylinders I3 accommodate the verticalcross members 36.

It will be noted that the rotatable valve shaft 25 carries a iiy wheel41 non-rotatively upon its lower end, as illustrated in Figs. 1 and' 2.A

screw-headed bearing member 48 anchored in the fiy wheel 41 serves as aconnection for one end of the connecting rod 43 so that duringreciprocation of the pistons28 and the carriage B said connecting rodwill be eiective for rotating the fiy wheel 41 and the valve shaft 25.

A/ bracket 58 is connected to the upper sides of the cylinders I3 bymeans of machine screws 5l. Said bracket has stub shafts 52anchoredtherein for the support of pinions 53. Pinions 53 mesh with asun gear 54 and also with a ring gear 55 which has a pitch line twicethe diameteras that of the sun gear. Sun gear 54 is keyed to the upperend of the shaft 25 by a key 56. A

castellated nut 51 prevents the gear 54 moving endwise from said shaft25. A cotter key 58 locks the nut 51 upon the threaded upper end ofshaft 25.

The ring gear 55 is secured by means of screws 59 to a plate 68 whichhas a downwardly projecting rib 6| which lits into a groove in the upperface of the" cylindrical upper end section 62 of the valve member 24.Rings 63 of packing material prevent the leakage of the working mediumpast the ends of the rotatable valve member 24. During operation of thedevice, while the pistons 28 and the shoe 34 are reciprocating, pressureapplied to the handle member I2 for forcing said shoe 34 toward asurface being treated is also impressed upon theroller bearings 64,Figs. 5, 6 and 7. Said bearings 64 comprisestemlike extensions 65 whichare journalled in the side walls of recessed bosses 66. Saidvbearingmembers 64 at the periphery of their spherical surface engage lowerouter.v wall surfaces of the cylinders I3 and roll therealong todiminish frictional resistance to forward and backward movement of theshoe 34 while pressure is applied at the handle I2.

The shoe 34 has flanges 61 and 68 at its ends for cooperating with theends of a clamp member 69, Figs. 1, 7 and 8. Said clamp member has afiat intermediatesection 10 and curled resilient end sections 1I and12'. Section 1I has an inturned flange 13 whereas section 12 has aninturned flange 14. Flanges 13 and 14 are sutilciently long that thecurled end sections 1I and 12 must be resiliently expanded before theshoe anges as 68 can be inserted as shown in Figs. 1 and 7. The solidlines at the left end4 of the clamp in Fig. 8 show the normal shape ofthe device whereas the dotted lines show the shape when the c urled endsection 1I is expanded to receive the shoe flange 61.

Preparatory to using the machine'a polishing y cloth or an abrasivebearing sheet or the like 15,

Fig. 8, is attached to the shoe by means of the clamp member 69. One end16 of the sheet 15 is i'lrst placed beneath the edge of in-turned flangeas 14 and thus clamped to the flange 68. The sheet 15 is then stretchedtautly along the outer periphery of the clamp member 69 and the oppositeend of said sheet carried beneath and beyond in-turned ange 13 whilesaid in-turned ange is expanded outwardly slightly further than thedotted line position shown in Fig. 8.

While holding that section of the sheet 15 in engagemnt with the edge ofinturned ange 13 tightly against said flange, the clamp member 69 ispermitted to spring inwardly to the dotted line position, Fig. 8,incident to stretching the I .sheet more tautly upon the clamping memberand clamping this end of the sheet firmly against the upper-side offlange 61. 'I'he ends of inturned anges 13 and,14 bite into the sheet15, thus holding it firmly in place upon the shoe during operation ofthe'rnachine.

Compressed air is a suitable working medium for the present machine,such air being introduced through a valve 80 having a control andshut-off member 8l, Fig. 2. In Figs. 1, 4 and 5 the machine is shown ina dead center position; that is, with the pistons 28 at the right limitof their reciprocal path of movement and with the connecting rod 43 indirect alignment with the axes of valve shaft 25 and the cross member 36upon which one end is journaled.

:Before starting, when it is in such dead center position, the operatorwill engage the upper end of valve shaft 25 and manually rotate the samecounter-clockwise. In this manner `the vfly vwheel 41 is rotatedcounter-clockwise to move the .connecting rod 43 off center. Thereafter,by manipulating the control member 8i of the valve 88, 4air underpressure is allowed to pass inwardly through the valve intake passage2|, Fig. 4. At this time the valve member 24 will be rotated clockwise ashort distance from the position illustrated, Fig. 4, and

' the air introduced into the passage 2l will be directed by said valvemember 24 through the left passage 21 and into the right end of the'left cylinder I3. Pressure of this air upon the carriage B to the left,the valve member 24 will be rotating clockwise, Fig. 4, and. at such aspeed that when the pistons 28 reach the limit of their movement to theleft said member 24 will be turned 9() degrees from the position shown.Such rotation of the valve member 24 is accomplished in the followingmanner. While the carriage B is moving to the left, the connecting rod43 will cause counter-clockwise rotation of the flywheel 41, Fig. 5.Valve shaft 25 and the sun gear 54 which rotate with the ywheel 41 willcause rotation of the fixed pinions 53 whereby clockwise rotation-willbe imparted to the ring gear 55. Thus the plate 68 and the valve member24 are rotated clockwise.

Since the pitch line of the sun gear 54 is onehalf the diameter as thepitch line of the ring gear 55 of the plate 68 and valve member 24 willbe rotated at one-half the speed as the y wheel 41. When the pistons 28move from the position shown in Fig. 4 to the opposite extreme limit oftheir movement the flywheel 41 will be rotated 180 degrees, whereas thevalve member 24 will be rotated 90 degrees. Therefore, when the pistons28 are in their left-most position the valve member 24, Fig. 4, will bein the position where its narrow edges will be aligned with the openings21 whereby the air under pressure in the passage 2| will be shut 0E fromthe left passage 21 and will be connected with the right passage 21 bythe chamiered section 28 shown uppermost in Fig. 4. The chamferedsection 28 shown lowermost in Fig. 4 will then be in registry with thelower side of the left passage 21 to permit discharge of the air fromthe left cylinder I3. Air directed from passage 2l into the rightcylinder I3 causes movement of the pistons 28 and the carriage B to theright.

Counter-clockwise rotation of the fly wheel 41 continues, wherefore,during this reverse movement of said pistons and carriage, the Valvemember 24 will continue clockwise rotation so that when the pistons 28are returned to the position shown in Fig. 4 the valve member 24 willhave been rotated 180 degrees. And since the valve member 24 issymmetrical in shape it will now be conditioned for a succeedingreciprocal cycle of the pistons 28. So long as the compressed air isadmitted to chamber 2l the pistons 28 will continue reciprocation andthe valve member 24 will be rotated in timed relation therewith fordirecting the air or working medium into the cylinders I3 at the propertimes.

Speed of the machine may be controlled by manipulating valve controlmember 8| to vary the amount of air introduced into passage 2l. The moreair admitted the faster will be the operation of the machine.

Air exhausted through the port 22 passes over the edges of the shoe 34where it is directed by the casing ange Illa. against the surface beingtreated to keep such surface free of loose abrasive particles or thelike which would interfere with the polishing process.

In Figs. 9 and 10 a different type of polishing member is connected tothe shoe 34 by means of the clamp B9. The surface treating sheet 83 ofsaid member instead of extending the full length of the clamp 69 to hookbeneath the inturned flanges 13 and 14, has its edges projected .betweenopposite longitudinal edge sections of said clamp and the lower face ofthe shoe. This sheet 83 is wrapped about a pad 82 which may be of spongerubber to adapt the sheet to conform to slightly irregular surfaceswhich are to be treated. Said pad 82 and the surface treating sheet 83may be attached together into a unitary assembly by means of an adhesivelayer between their contiguous surfaces. The lower edge sections of theshoe 34 and the upper longitudinal edge sections of the clamp member 59may be roughened so as to bite into the edge portions 84 and 85 of thesheet 83 so that the latter will be held firmly in position upon theshoe.

I claim:

1. A polishing machine comprising a portable casing, a motor in saidcasing including axially aligned cylinders secured to said casing, therebeing axially extending slots in side wall portions of said cylinders,valve means rotatable between said cylinders to alternately admit aworking medium thereinto, a member rotatable to transmit driving forceto said valve means pistons in said cylinders, a work member, meansprojecting through a slot in each of said cylinders for operativelyconnecting said pistons with said work member, and a connecting rodconnected with said pistons for reciprocal movement therewith andconnected eccentrically with said rotatable member to impart rotativemovement thereto during reciprocal movement of the pistons.

2. In a polishing machine, the combination of paired axially alignedcylinders, pistons respectively in said cylinders, a valve memberbetween said cylinders and continuously rotatable in one direction toalternately direct a working medium into said cylinders to causereciprocal movement of the pistons, a work member attached to both ofsaid pistons and movable in unison therewith, and means propelled bysaid pistons for imparting such continuous rotative movementto saidvalve member.

3. In a machine of the class described, the combination of pairedaxially aligned cylinders, pistons respectively in said cylinders, avalve casing comprising a cylindrical valve chamber between saidcylinders and'having diametrically opposite cylinder ports respectivelycommunicating with said cylinders, said valve casing also havingdiametrically oppositely disposed intake and exhaust openings eachspaced 90 degrees from said ports, a Valve core within and rotatablecoaxially of said chamber, said valve core having diametrically oppositefaces conforming to and adapted to sweep about the cylindrical wall ofthe chamber during such rotation, said faces being of substantially thesame dimensions circumferentially of said wall as said ports and saidopenings, said valve core being so adjusted with respect to said pistonsthat the said diametrically opposite faces are substantially alignedwith said openings while said pistons are at onc reciprocal limit, andmeans driven by said pistons and operable to rotate said valve corethrough 90 degrees during each movement of the pistons from eachreciprocal limit to the other.

4. In a machine of the class described, the combination of a cylinder, apiston reciprocally in said cylinder, a valve casing adjacent to saidcylinder and including a cylindrical valve chamber having passages forconducting a piston propelling medium to and from said cylinder, a valvecore within and rotatable coaxially of said chainber for directing suchmedium into and from said passages to reciprocally propel said piston,rotatable inertia means connected with said valve core, and means drivenby said piston for rotating said inertia means and said valve core inselected time relation therewith.

5. In a machine of the class described, the combination of a cylinder, apiston reciprocally in said cylinder, a valve casing adjacent to saidcylinder and including a cylindrical valve chamber having passages forconducting a piston propelling medium to and from said cylinder, a valvecore within and rotatable coaxially o1' said chamber for directing suchmedium into and from said passages to reciprocally propel said piston, avalve shaft extending axially through said valve core, a sun gear uponsaid shaft adjacent to one 'end of the valve core, av ring gear aboutsaid sun gear and drivlngly connected with said core, idler gears meshedwith said sun and ring gears, and means driven by said piston forrotating said shaft. said driven means engaging said shaft adjacent tothe opposite end of the valve care, and the pitch line of said sun gearbeing onehalf the radius of that of the ring gear whereby the valve coreis driven at one-half the speed of the valve shaft.

6. In a machine of the class described, the combination of pairedaxially aligned cylinders, pistons respectively in said cylinders, avalve casing comprising a cylindrical valve chamber between saidcylinders and having diametrically opposite cylinder ports respectivelycommunicating with said cylinders, said valve casing also havingdiametrically oppositely disposed intake and exhaust openings eachspaced degrees from said ports, an axially bored valve core within androtatable coaxially of said chamber, said valve core havingdiametrically opposite faces conforming to and adapted to sweep aboutthe cylindrical wall of the chamber during such rotation, said facesbeing of substantially the same dimensions circumferentially of saidwall as said ports and said openings, said valve core being so adjustedwith respect to said pistons that the said diametrically opposite facesare substantially aligned with said openings while said pistons are atone reciprocal limit, a valve shaft extending through the bore in saidvalve core, a sun gear upon said shaft adjacent to one end of the valvecore, a ring gear about said sun gear and drivingly connected with saidcore, idler gears meshed with said sun and ring gears, and means drivenby said pistons for rotating said valve shaft degrees during eachmovement of the pistons from each reciprocal limit to the other, and thepitch line of said sun gear being one-half that of the ring gear wherebythe valve core is driven at one-half the speed of the valve shaft. c

'7. In a machine of the class described, the combination of pairedaxially aligned cylinders each having a pair of diametrically oppositeaxially extending slots in side wall portions thereof, pistons in saidcylinders, a cross-member on each of said pistons and having endportions projecting outwardly of the cylinder walls through said slots,a yoke at one side of the cylinders and connected with projecting endportions of said cross-members, a work member at the opposite side ofthe cylinders and connected with the opposite end portions of saidcross-members, a valve casing comprising a cylindrical valve chamberbetween said cylinders and having diametrically opposite cylinder portsrespectively communicating With said cylinders, said valve casing alsohaving diametrically oppositely disposed intake and exhaust openingseach spaced 90 degrees from said ports, a valve core within androtatable coaxially of said chamber, said valve core havingdiametrically opposite faces conforming to and adapted to sweep aboutthe cylindrical wall of the chamber during such rotation, said facesbeing of substantially the same dimensions circumferentially of saidwall as said ports and said openings, said valve core being so adjustedwith respect to said pistons that the said diametrically opposite facesare substantially aligned with said openings while said pistons are atone reciprocal limit, and means driven by said pistons and operable torotate said valve core through 90 degrees during each movement of thepistons from each reciprocal limit to the other.

8. In a machine of the class described, the combination of pairedaxially aligned cylinders each having a pair of diametrically oppositeaxially extending slots in side wall portions thereof, pistons in saidcylinders, a cross-member on each of said pistons and having endportions projecting outwardly of the cylinder walls through said slots,a yoke at one side of the cylinders and connected with projecting endportions of said cross-members, a work member at the opposite side ofthe cylinders and connected with the opposite end portions of saidcrossmembers, a valve casing comprising a cylindrical valve chamberbetween said cylinders and having diametrically opposite cylinder portsrespectively communicating with said cylinders, said valve casing alsohaving diametrically oppositely disposed intake and exhaust openingseach spaced 90 degrees from said ports', an axially bored valve corewithin and rotatable coaxially of said chamber, said valve core havingdiametrically opposite faces conforming to and adapted to sweep aboutthe cylindrical wall of the chamber during such rotation, said facesbeing of substantially the same dimensions circumferentially of saidwall as said ports and said openings, said valve core being so adjustedwith respect to said pistons that the said diametrically opposite facesare substantially aligned with said openings while said pistons are atone reciprocal limit, a valve shaft extending through the bore in saidvalve core and through said casing, a sun gear upon said shaft a-t oneside of the casing, a ring gear about the sun gear and drivinglyconnected with the valve core, idler gears meshing with said sun andring gears, and means driven by said pistons for rotating said valveshaft 180 degrees during each movement of the pistons from eachreciprocal limit to the other, and the pitch line .of said sun gearbeing one-half that of the ring gear whereby the valve core is driven atone-half the speed of the valve shaft.

ERNST AHLSKOG.

